Kite boarding, sometimes also referred to as kite surfing, is an extreme sport whereby a person uses a kite, generally having a “C” or modified “C” shape. Such shape, also termed “a leading edge inflatable kite”, is created by using a hand or electrically operated pump to inflate an elastomeric bladder contained within a protective cover material forming the kite's leading edge. The kite's leading edge, which forms a rigid C-shaped 4-8 inch diameter round tube when inflated, also has one or more orthogonally aligned abutting struts, which structure supports the fabric material forming the kite canopy. Kites are deflated for packaging and transport. During use, the kite's leading edge and struts are inflated to about 3-8 lbs. above ambient atmospheric pressure. The leading edge bladder and struts can be inflated simultaneously, or separately.
Without inflation, or low inflation, a kite becomes floppy in the water, with some wind drag, but cannot create an aerodynamic shape.
Modern prior art kites are attached to 4 (or 5) lines, which lines are generally 10-30 meters in length, and are also attached (tethered) to the kite rider, who is wearing a special harness, allowing the kite rider, while standing on a surfboard-like device, to be pulled along the surface of the water due to wind powering the kite.
Besides water-based kite boarding, kites are also used on land where the rider stands on a skateboard type device (with wheels) travelling on, for example, packed sand, or sitting in a device with wheels for travel over a hard surface. Recently, kites have also been deployed by snow boarders for use over snow-covered areas.
U.S. Pat. No. 4,708,078 by Legaignoux, et al. teaches the first use of a kite design that can be re-launched from the water surface, which key innovation spurred the sport of kite boarding.
Subsequent innovations seek to improve on re-launching the kite from the water surface, such as, for example, U.S. Pat. No. 7,104,504 B2 by Peterson et al. which describes a system whereby the kite rider can use a dedicated line (or piggybacking onto one of the existing lines) to adjust the kite canopy profile to exhibit different aerodynamic characteristics to facilitate re-launching the kite.
FR 2,762,583 describes a mechanical system that allows the kite rider to partially de-power the kite by moving the control bar towards the kite, or by completely letting go of the control bar. Since the control bar is attached to the outside (steering) lines, this action changes the ratio of the outside steering lines (which lines are connected to the kite wingtips) to the inside (front) lines (which lines connect the kite's leading edge to the kite rider's harness), thus changing the kite shape and aerodynamic lift.
Subsequent innovations, for example, U.S. Pat. No. 6,830,220 B2 by Runyan disclose a quick release system whereby the kite rider can pull a lever at the control bar, which lever is connected to a wire, which wire pulls out two (or four) pins to disconnect the outside (steering) lines, or, in another embodiment, both the outside and inside lines. However, a potentially very dangerous scenario is created if the (inflated) kite lines and control are totally released, enabling the kite to fly freely. Although U.S. Pat. No. 6,830,220 B2 refers to the “deflation” of the kite when the disclosed release system is activated, this reference actually refers to de-powering the kite, as there is no reference, or mechanism, disclosed, that would or could de-pressurize and thus deflate the kite.
An additional prior art feature allows the kite rider to adjust the de-power range by pulling and locking a trim line connecting the center (inside) lines to the kite rider's harness. For example, Logosz in U.S. Pat. No. 7,621,485 B2 discloses a user adjustable trim line which the user can adjust and mechanically fix while flying the kite.
The prior art technology also allows the kite rider to disconnect from the inside lines by manually unhooking the inside lines, or by activating a release mechanism (see for example U.S. Pat. No. 6,988,694 by Bans, et. al. and U.S. Pat. No. 6,691,954 by Harrington, et al.). These maneuvers, combined with letting go of the control bar, causes the kite to partially de-power, by creating slack in two (or three) of the four (or five) lines while the kite rider still remains tethered to the kite by only one (or two lines).
Once the kite rider disconnects from the inside lines, and lets go of the control bar, an (elastomeric) leash line connects the kite rider to one (or two) lines tethered to the kite. In this scenario, the kite is partially de-powered, and is still tethered to the kite rider.
For the scenario where the kite rider is still tethered to the kite by the two inside lines, the kite can still exert tension on these lines, especially if the wind velocity increases or the wind gusts.
To address the issue of enabling a kite rider to maximize de-powering a kite while tethered, U.S. Pat. No. 7,971,829 B2 by Dano See, et al. describes a kite de-powering system to provide additional de-power range by allowing only one of the center (inside) lines of a four line kite system to connect to the kite. An aspect of this invention is that this one-tether line design is configured to minimize the potential for tangles and twists.
In another variation of extending the de-power range of a kite, Logosz et al. in U.S. Pat. No. 7,581,701 B2 presents a pulley system that creates twice the relative change in length between the front lines and the steering lines, compared to the prior art, which, according to the authors, provides for a nearly complete de-powering of the kite while in flight.
In yet a further variation, Eberle, et al. in U.S. Pat. No. 7,810,759 B2 describe a kite line system containing a supplementary line that acts as a third front line while the kite is in flight. The authors claim that such a third front line acts to stabilize the geometry of the kite, acts as a depower line, and assists in re-launching the kite from the water surface. However, during a kite crash that rotates the kite through 360°, the use of a third front line will wrap around the kite, with the risk of cutting (and severing) the kite, and preventing the kite from being re-launched. For re-launch, the third front line needs to be disconnected, in-situ, by the kite rider.
However, even in the scenario where the kite is depowered using prior art methods, the kite retains its aerodynamic shape, and in windy or gusty conditions can suddenly fly off the water, or strongly move along the surface of the water, with considerable tension exerted on the lines. In this situation, standard practice is to have the kite rider slowly pull along towards the kite using one (or two lines), to retrieve the control bar, and then wrap the lines around the control bar such that only one line is taut between the control bar and the kite. This action allows the kite rider to slowly move along towards the kite, grasp the kite and then use the kite as a flotation device for a self-rescue, which self-rescue procedure is well known by those skilled in the art.
If such a self-rescue procedure is not possible due to, for example, a sudden (unmanageable) increase in wind velocity while on shore or in the water, during high wave conditions, harness bar failure, kite line failure, tangled lines, or being dragged towards rocks or towards the shoreline, it becomes prudent for the kite rider to completely disconnect from the kite.
Such total disconnection from the kite can be done by first letting go of the control bar, disconnecting from the inside lines, and then activating a leash release device (or manually detaching the leash line). This action causes the kite to freely stream away, with the control bar and kite lines still attached to the kite. Such a free-drifting kite can be dangerous to others in the water, or persons on shore, who may become caught or entangled in the kite lines or control bar being dragged uncontrollably behind the kite. In such a scenario, the kite's leading edge is still air-inflated, with the kite maintaining its aerodynamic shape, and able to power-up and create high tension in the lines if the kite or control bar become snagged.
If the kite rider becomes entangled in the lines, even disconnecting the leash release device may not allow the kite to totally release and disconnect. Some kite riders carry a knife to cut the lines during this potentially very dangerous scenario, which can be fatal.
Thus, a key safety issue in the sport of kite boarding is the danger of the kite rider being unable to sufficiently de-power the kite while being dragged along on the water, on shore, over rocks, entangled with the lines of another kite, or to disengage the kite completely in the scenario where the kite rider is entangled in the lines.
The current invention addresses the key safety issue of being able to sufficiently de-power an air-inflated kite by enabling the kite rider to quickly de-pressurize the kite's air-pressurized leading edge bladder, thereby causing the kite to lose its aerodynamic shape, and greatly restrict the kite's ability to catch wind and power-up.
That and other objects of the invention will be better understood by reference to the detailed description of the preferred embodiment which follows. Note that not all of the objects are necessarily met by all embodiments of the invention described below or by the invention defined by each of the claims.